1. Technical Field of the Invention
The present invention relates to an XY plotter apparatus capable of displaying specified characters and figures at a high speed on a magnetic panel.
2. Prior Art
It is known that a conventional XY plotter apparatus draws a figure on a surface of a common recording form by using a writing tool such as, for example, an ink pen. In other words, the writing tool is held at a position where it lightly contacts the recording form and its operation is controlled by the writing tool drive. The writing tool drive is intended to drive the writing tool in the X-axis direction and the Y-axis direction, respectively, and can draw a desired figure on said recording form by supplying a signal for which relevant data has been processed as to a figure to be drawn to said writing tool drive. In this case, it is necessary to move the writing tool to a certain specified position to display a next line after the display of a line has been completed. At this time, the writing tool is slightly moved away from the recording form by the writing tool drive and the coordinate signals for X and Y-axis directions which show a new position can be applied to the writing tool drive. Though a time required to display a figure is relatively short, a figure drawn once on the recording form cannot therefore be erased and the recording form should be replaced.
On the other hand, a practical use of a "magnetic panel" has been promoted. This magnetic panel is made up by sealing a dispersion liquid (commonly presents a white color) which dispersingly suspends fine magnetic particles (which commonly presents a black color) between two plates, at least one of which is transparent, and a magnetic field is applied to the dispersion liquid from one of the two plates by the magnetic pen employing a permanent magnet. (Refer to Tokkai Sho 54-14193 Bulletin on which the patent application by the same applicant as the present invention is filed.) When a magnetic field is applied, magnetic particles are attracted to the magnetic field to present a contrast between the black color of magnetic particles and the white color of the dispersion liquid and this contrast can be identified as a figure. In other words, the dispersion liquid presents a more black color only at a position to which the magnetic field is applied by the magnetic pen. Any XY plotter apparatus capable of repeating the display can be obtained by replacing this magnetic pen with the writing tool of said XY plotter apparatus and the magnetic panel with the recording form. In this case, since the displaying magnetic field is applied to the magnetic panel by making the magnetic pen close to the magnetic panel, the magnetic pen must be moved away from the magnetic panel when moving the magnetic pen to another position for another display after a figure has been displayed. (This is so as to move the magnetic pen without applying its magnetic field.) The magnetic pen which has been moved to the specified position is made to again approach the magnetic panel and therefore a large movement of the magnetic pen in the vertical direction with reference to the magnetic panel results in a substantial reduction of the displaying speed of a figure.